EventLogQuery: How to form query string?

问题:

I have the following code:

string query = "???";

EventLogQuery elq = new EventLogQuery("Application", PathType.LogName, query);
elq.Session = new EventLogSession("x.x.x.x");
EventLogReader elr = new EventLogReader(elq);

I'm trying to figure out what I need to set query to in order to look for all entries with a source of "SQLSERVERAGENT".

回答1:

I have just spent an hour trying to solve similar for myself and thought I would contribute back with the solution for anyone else that comes this way. The comments should be fairly self explanatory.

  public void ReadSqlAgentEventMessages()
        {
            // Force culture to en-US if required, some people get a null from FormatDescription() and this appently solves it. 
            // My culture is set as en-GB and I did not have the issue, so I have left it as a comment to possibly ease someone's pain!
            // Thread.CurrentThread.CurrentCulture = new CultureInfo("en-US");

            EventLogQuery eventlogQuery = new EventLogQuery("Application", PathType.LogName, "*[System/Provider/@Name=\"SQLSERVERAGENT\"]");
            EventLogReader eventlogReader = new EventLogReader(eventlogQuery);

            // Loop through the events returned
            for (EventRecord eventRecord = eventlogReader.ReadEvent(); null != eventRecord; eventRecord = eventlogReader.ReadEvent())
            {
                // Get the description from the eventrecord. 
                string message = eventRecord.FormatDescription();

                // Do something cool with it :) 
            }
        }